Epidemiological studies have long implicated the human papillomavirus (HPV) as a major cause of cervical neoplasia and cancer. Nonetheless, it has been only within the last decade that a vast body of evidence has been generated to support a causal role of HPV in the etiology of cervical neoplasia and cancer. More than 100 types of HPV have been identified. However, not all HPV types are implicated in cervical cancer. Several types have been associated with a high risk for cervical disease, including types 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, and 70. The detection of these high-risk types of HPV is important in the accurate and timely diagnosis of HPV-related diseases.
Consequently, a variety of methods for detecting high-risk types of HPV have been devised. Many of those rely on the detection of unique sequences in the HPV genome. For example, DNA or RNA probes complementary to a portion of the genes of a particular high risk HPV strain have been reported in the art, e.g., in U.S. Pat. No. 4,849,332 to Lorincz, incorporated herein by reference, as useful in screening for the presence of a particular strain of high-risk HPV in patient samples. U.S. Pat. No. 5,705,627 to Manos et al., incorporated herein by reference, reports use of polymerase chain reaction (PCR) to amplify and detect HPV DNA using degenerate or mixed consensus primers, followed by typing using a mixture of genotype-specific DNA probes. Other examples of using consensus primers can be found in U.S. Pat. No. 5,364,758 to Meijer et al., and Kleter, B. et al., Am. J. of Pathology, vol. 153, No. 6, 1731-39 (1998). These references are also incorporated herein by reference to the extent applicable.
PCR amplification provides a more sensitive method of detecting HPV DNA, but because existing PCR consensus primers hybridize to both high-risk types of HPV and low-risk types, the need for subsequent typing still exists. Using a cocktail of probes specific for various high-risk genotypes, on the other hand, is costly, time-consuming and requires large quantities of reagents and sample DNA. Therefore, there exists the need for a more economical method of detecting all the high-risk HPV types that are of concern.